The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Multiple antenna elements are needed for various on-vehicle services. For example, a vehicle may carry systems for satellite-based navigation, satellite radio, AM/FM radio, mobile communication network communications and other types of services. Those different systems may need different antennas to receive or transmit wireless signals. The U.S. Pat. No. 9,178,272 disclosed a vehicle-roof-mounted multiband shark fin antenna that may include multiple receiving or transmitting antenna elements.
On-vehicle antennas can be mounted on an outer surface of a vehicle roof. The conductive roof or other planar surfaces of the vehicle can serve as a ground plane for the antennas. For some types of antennas, increasing the size of the ground plane can improves performance of the antenna.
During an antenna design process, antennas are evaluated and tested in the field or in a controlled environment to determine or optimize design parameters. A size of an antenna ground plane may need to be varied for conducting the evaluation or test operations.